


Muscle-Bust Dust

by BioYuGi



Category: RWBY
Genre: Big Breasts, Breast Expansion, F/F, Large Breasts, Large Muscles, Muscle Growth, White Rose - Freeform, big boobs, large boobs, muscle fetish
Language: English
Status: Completed
Published: 2019-09-24
Updated: 2019-09-24
Packaged: 2020-10-27 06:14:48
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,317
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20755676
Author URL: https://archiveofourown.org/users/BioYuGi/pseuds/BioYuGi
Summary: This story features one of my lesser-done fetishes, but one I can still appreciate at times. Some large muscle growth, with additional BE action featuring my favorite RWBY girl.Based on a picture drawn by Dagwam, and colored by EspadaDelOscuro: https://www.deviantart.com/espadadeloscuro/art/Weiss-751804858





	Muscle-Bust Dust

"Pyrrha are you sure that you can't do it? What if we doubled the payment for endorsement?" Weiss Schnee, heiress of the Schnee Dust company chased after her idol. Pyrrha Nikos was tall, athletic, smart, kind, clever, basically any adjective that Weiss could think of, rolled into one incredible redhead ace of the academy. Pyrrha turned around, looking nervous but trying to let Weiss down gently.

"I'm sorry, Weiss. But I still feel guilty about sponsoring Pumpkin Pete's. My teeth had bits of marshmallow stuck in them for hours after filming that commercial." The toned woman smiled shyly at Weiss.

"Okay that I understand, but the new MB dust is simply meant to be a muscle booster, it's a good product!" 

"I trust you, Weiss, but it's just, well. I don't want to try and get ahead in life through some sort of stimulant." Weiss lowered her hand as she was about to bring up another point to try and get the girl's favor. She turned her head to the side and blushed. "I don't oppose anyone else who might use them, especially if they're a Hunter or Huntress who simply wishes to better themselves, but it's not for me. You may have more luck with one of the veteran students?"

"No, you would have been the one." Weiss sighed and slumped forward. "Sorry to bother you, Pyrrha. But if you reconsider, please let me know!" Pyrrha nodded, knowing she wouldn't, and let Weiss be. The white-haired girl looked at the bottle of blue dust in her hand and scowled.

"Who else would want to try this out?" she asked, walking back to her room. "MB Dust." The label had been damaged when the sample was sent to her, but she clearly saw 'Muscle B st Dust' on the paper. It clearly was a muscle booster, and she thought that Pyrrha would have been perfect to test it. Such a prominent sponsor would have helped Weiss stay in her family's good standing at the very least.

"Hm. I suppose I may as well try it out myself," she admitted. Weiss had skill but her aura was the weakest of her group. If she was to stay on even ground with Blake, Yang, and even Ruby, she'd need some assistance. "I wonder why Whitley sent this to me," she thought, checking the box again. "Probably as a gag. Calling me underdeveloped," Weiss muttered. "Well if it helps!"

Weiss unscrewed the top of the dust container and poured the dark blue powder onto her head. She felt it sink into her skin and waited a moment.

"Or it could be a dud and my idiot brother just made me pour glitter on my head!" Weiss yelled, throwing the empty container in the trash.

"Uh-oh, Weiss is angry again!" her roommate said as she came through the front door. Weiss sighed. Ruby's chipper attitude might actually improve her mood at the moment.

"I'm not angry. Just, Ruby, do I look any bigger to you?" Weiss asked. She pulled one of her silken sleeves down past the elbow to see if there was any improved musculature. Ruby peered close at Weiss, but instead of looking at her arm, Ruby peered right into Weiss's chest, until her nose almost poked at Weiss's tiny cleavage.

"Er, well I don't really check here all that often, Weiss, but I don't think so!" Ruby exclaimed. Weiss blushed and grumbled.

"That's not what I mea-" Weiss felt her chest bump into Ruby's face, and the black-haired girl took a step back. "Ruby!"

"Um, I think I was mistaken! Yay." 

"What do you-" Weiss looked down at her chest, and saw two small bumps where there had been tinier dents before. Breasts on par with Ruby's. "Wait. That's not supposed to happen."

"Weiss, is there something I'm missing here?" Ruby asked curiously. Weiss shook her head.

"My brother sent me a new muscle booster dust, but I'm not sure what it means. Oh, wait. Clearly my pectorals have improved! That's all," Weiss said confidently. Despite her claim that the musculature under her boobs had grown larger, the white-haired beauty's chest did seem softer, and rounder as well.

"So I suppose it did work, however minor it-" Weiss was cut off yet again as Ruby suddenly had her hand on Weiss's arm. She ran her fingers up and down the pale skin, making Weiss confused until she saw what Ruby noticed. Muscles. Bulging, firm muscles protruding from her forearm. Weiss gasped and saw them swell larger every few seconds. Ruby was mystified, her hands running along the growing thickness of Weiss's left limb as it doubled in size.

"R-Ruby, what are you doing? Unhand me!"

"Weiiiiss," Ruby cooed, rubbing her cheek along the growing bicep as it stretched out Weiss's sleeve. "Your arms are so big and soft~" the younger girl exclaimed, smiling giddily and letting out a distressingly-satisfied groan.

"Um, wait, how are they soft?" Weiss asked. She flexed her right arm before her eyes and watched the bicep bulge out like a softball. Her eyes widened in shock. With Ruby still massaging her growing left arm, Weiss brought the right limb up to her face and rubbed it against her cheek. The muscle underneath was hard as steel, yes, but the skin on top was extra-soft. Even Weiss felt a difference, and her flesh was typically well-cared for already.

"Well this will certainly make fighting easier," Weiss mused. She was slightly distressed at how big her arms got, but it was still within reason. Until her bust suddenly doubled in size yet again and stressed the confines of her top, with two huge scoops of vanilla ice cream that still steadily encroached further. "Um, Ruby?"

"Hang on," Ruby protested, squeezing the meat of Weiss's thick upper arm and tracing it down to the wrist. When she looked up at Weiss's boobs on the path to eclipse Yang's, she blinked a few times. "Ohhh, well that's gonna upset sis," she noted. "But with these new muscles~ You're bound to match her in a fight! She'd probably still win though."

"Ruby this is not at all what I had in mind when I used this dust!" Weiss proclaimed. She shuddered as Weiss's shoulders were thrown back and she felt her deltoids thicken up, bulging with new muscles that extended from her neck to her shoulders. She turned her head and felt them swell again, and then the transformation spread down to the small of her back. Every few seconds Weiss contorted her body as she felt muscles appearing all along her torso.

"Ah, h-hey, ah, w-wait, this, ah, shouldn't f-feel so good!" the heiress exclaimed. She stretched her arms out as the sleeves shrunk down low on her arms, and tightened up. Her muscles were too big for the garment to easily keep her arms covered. Weiss felt her waist pinch in, and then explode out with new iron-clad abs that spread from her navel up to her chest, which still swelled outward. Weiss's hands now looked tiny on her chest. When she put them on her bosom, they only covered half a tit each, and pushing into their soft expanse revealed that there were massive deposits of pectoral steel hidden beneath.

Ruby's eyes lit up like fireworks and she stood on her tiptoes to look up at Weiss. Her mouth hung open and she drooled over herself as her hands went to Weiss's stomach. When the scythe-user dragged her nails across her friend's stomach, she felt them barely make a nudge in the six-pack Weiss gained. A squealing sound came out of Ruby's lips as her hands went to Weiss's thighs, which also had cascaded to the side with rippling mounds of dense muscle.

"Muscleeees~" Ruby moaned, licking her lips. Weiss looked slightly uneasy but the constant waves of pleasure coursing through her body made it hard to be too upset at Ruby's lascivious intrigue in her growing musculature. "Weisssssssssss." Ruby's voice got so high-pitched that the older woman couldn't hear it very well.

"Y-Yes Ruby?" Weiss moaned, flexing her toes as her calves straightened up like tungsten rods. Weiss felt her booty clench up, and when the tension released, each cheek shot out several inches back, with buns like corded ropes of metal resting underneath a soft layer of skin. "Ooh, hah. My backside too?"

"Steel buns!" Ruby zipped behind Weiss and gave two firm squeezes of Weiss's booty, making the heiress moan. She felt her hips crack a bit as her thighs and waist were further enhanced, and gave her extra height to compensate as well. Weiss thought for a moment that she was on her tiptoes as well, when Ruby zipped back to the front and had her hands on Weiss's breasts. The girl barely came up to Weiss's bosom, and the heiress realized how close the ceiling had gotten. "And pillow breasts! Gah, but they still look so tough! How is that possible?!" Ruby freaked out and spun in a circle before face-planting in Weiss's rack.

"R-Ruby, please, control yourself!" Weiss declared, though she admittedly had a rough time dealing with the sensations of her changes as well. Staring down at Ruby and realizing that she'd shot up more than two feet taller than the smaller girl gave her a rush of adrenaline. Noticing that her skirt now had risen up to only cover a scant few inches of powerful, melon-crushing thigh gave Weiss a rush of something else.

"Kya! Sorry Weiss!" Ruby backed off, her hands nervously wiggling through the air like she was playing an invisible keyboard. "It's just, gah, look how strong you are now! You're like some huge, muscly, swordy, busty…. Grimm-killing machine!"

"The busty bit is concerning," Weiss admitted, even though her heart rate skyrocketed when she looked down and saw her hooters sticking out a foot and a half from her chest. Each mound dominated her torso. Their lowest curves even covered some of her sweet abs, which seemed to her to be the only detriment they offered so far. Feeling her back, she definitely was muscled enough to not worry about back pain or loss of support…

"It's just supposed to be a muscle booster, why would this make me so, nnghgh! Ah!" Weiss let out another powerful moan as her boobs extended further still, and a last surge of muscle growth rippled through her body. Her upper arms were thicker than her torso ever was, and her lower arms were barely behind those. Weiss's entire lower body felt like she could crack the floor if she wasn't careful, but looking down at her larger feet, she was grateful that she hadn't been wearing her heels at the time, just a pair of slippers she'd carelessly burst out of. Ruby rocketed to the trash can and removed the container the dust had been held in originally.

"This one?" Ruby asked, looking at the bottle and bouncing on her feet. "Muscle-Bust Dust?"

"What? No no, it says 'Muscle Boost Dust'." Ruby stretched out her arm and placed the empty bottle in Weiss's cleavage. "...Oh." A bit of the label hadn't been removed, just scrunched up, and when Ruby fixed it, the real name of the product was clear. "W-Well. I suppose this is a glowing endorsement for the Schnee Dust company," Weiss proclaimed. 

"Oooh gosh you're telling me," Ruby said, staring, transfixed at Weiss. Weiss noticed and smirked, squeezing her forearms into her bosom to make her prominent bust even more obvious.

"So Ruby," Weiss said with a smug look on her face. "You're into muscles?" 

"Yessssss…" the younger girl admitted, looking hypnotized by the display. Some of Weiss's sleeves finally ripped, unable to contain the enormity of the biceps underneath.

"Well, after growing that much, I'm pretty sore," Weiss began. "Do you think you could-"

"Yes! Yes! Land of ten thousand yeses!" Ruby yelped. She quickly went down on her knees and grabbed one of Weiss's thighs. One arm was barely able to wrap around the thickest part, but she used both and let out a shudder as her cheek grinded against the toned muscle. "Ohohohoho…" Her hands ran up and down like she was polishing a giant silver candlestick, taking care to squeeze and rub in just the right way. 

The privacy of the two was interrupted when the door opened up with a slam. Weiss, thinking quickly, grabbed Ruby and tossed her into the top bunk. The act of tossing the other girl had been as easy as throwing a wadded-up piece of paper. Weiss dashed to the bed as well, and regretted the action when she heard one of the bedposts snap, then another, leaving her bed at an angle as Yang and Blake came in.

"Hah, hah," Yang pat Blake on the back as the two came in and went over to their side of the room. Blake landed on her bed, exhausted and sweating. "Good workout, Blakey."

"I'm gonna die," Blake declared, her voice muffled by her sheets. Yang took a deep breath and looked at the box on one of their beds.

"Ooh, Weiss, get a present from home?" the blonde asked.

"Y-Yes," Weiss said, covering herself up with her bedding. She needed both the sheet and blanket separated to come close, or her enormity would be discovered instantly. Weiss wasn't sure why she was hiding her size, but felt kind of awkward about it in front of people who weren't Ruby… "Just a… just a little trinket."

"Wow. More than a trinket!" Yang reached right into the box and pulled out a handful of small bottles. "There's enough here to be declared a buttload. You gonna share, Weiss?" Weiss heard a high-pitched noise that came from above her bed. So high that it was nigh-imperceptible. The heiress blushed. She had a feeling she'd be sharing a lot of it.


End file.
